The invention relates to an auxiliary device for use with a seam weaving machine serving to join the ends of a synthetic resin fabric flat-woven from longitudinal and transverse threads by forming a woven seam. Such a woven seam is formed from the exposed ends of the longitudinal threads used as weft threads and from the auxiliary warp threads in a weaving operation by means of the seam weaving machine. The auxiliary device serves to couple the auxiliary warp threads to tensioning strings in order to exert the required tension on the auxiliary warp threads required for forming the shed.
In general, transverse threads are used as auxiliary warp threads which are obtained by fraying a strip of the fabric to be provided with a woven seam. Said transverse threads have only limited length, namely a length corresponding to the width of the synthetic resin fabric. The weights used for tensioning the auxiliary warp threads therefore cannot be fastened to the auxiliary warp threads themselves and are fastened to tensioning strings which, in turn, are coupled to the auxiliary warp threads.
Regarding the seaming technique for joining the ends of flat-woven papermachine fabrics reference is made generally to the publication by B. Krenkel in "Das Papier", No. 3, 1984. page 100 et seq. An automatically operating seaming machine for synthetic resin fabrics is described in EP-B-O No. 043 441 where before the beginning of the seam of each papermachine fabric a multiplicity of very closely spaced auxiliary warp threads (up to 448 auxiliary warp threads) are individually tied to or adhered to the ends of the tensioning strings. The tensile force on the individual auxiliary warp threads required for the seam weaving operation ranges between about 70 and 240 N, depending on the type of fabric, and is generally achieved in that each tensioning string end is weighted with a corresponding weight. This tying or adhering of a multiplicity of auxiliary warp threads to tensioning strings is not only very time-consuming but it also brings about the risk of confusion or other imperfections which are not noticed until after weaving and which therefore can be eliminated only with great difficulties later on. If the thread ends are manually adhered or tied together an excessively high tension is easily exerted on the auxiliary warp threads, which may be so high as to cause breakage of the thread.